The Republican. [volume] (Oakland, Md.) 1877-current, 1887-02-19
ABOUT EARTHQUAKES.
Theories Advanced by One OF tho Worlds
Most Famous Scientists.

Most Famous Scientists.
1t is manifest that the initial impulse
fan earthquake must be due to some
sudden and violent origin. Various
causes may be conceived as possibly
producing the shock. For example,
when the roof of a subterrancan cavity
collapses a conclusion must be produced
which may have the effect of an earth
J cake at the surface. In limestone
codntries, such as Carniola, the ground
is honeycombed with grottoes and pas
sages, and slight shocks of earthquake
are of frequent occurrence, due, no
doubt, to the falling in of some of these
underground caverns. More violent
effects might arise from the collapse of
large emptied volcanic reservoirs, as
perhaps has occurred at the extinct
volcano of Ischia. Again, the rocks of
the crust are in state of continuous
strain due to various causes, and
especially to the gradual contrac-
ton that arises from the slow
cooling of the planet. From time
to time there probably come moments
when they can no longer bear these
stresses, and when consequently they
snap asunder and readjust themselves
in new position of equilibrium. A
slight dislocation OF this kind would I'M
doubtedly set in motion series of earth
quake waves that might devastate the
country far and wide, while a more ex-
tensive fracture might produce such
catastrophe as man has never yet
witnessed. Such sudden ruptures of
rocks are not impossibly the sources Of
the earthquake shocks so frequently eX-
perienced in mountainous countries.
Along the range of the Alps, for in
stance, subterranean disturbances are
of common occurrence, varying in force
from hardly perceptible tremors up to
smart and more or less destructive
shocks. That mountain chain has a
long and most interesting history, which
takes us back to the early beginning of
the shaping of what is now the European
Continent. Instead of having been
produced by one primeyal uplift,
the Alps have been upheaved again
and again, and during the inter-
walls of repose their crests and
decliyities have been slowly worn down,
as they still are to-day by frost and
rain, springs and brooks, rivers and
glaciers. Yet the repose has only been
comparative. That intense crumpling
and contortion, the proofs of which the
tourist gazes at with wonder along the
mountain sides that plunge down into
the Lake of the Four Cantons, has left
the rocks below in state of strain
from which relief is at intervals OBJ
tanned by sudden snap or crack.
Whether or not any local change Of
level may be appreciable, either in the
way Of elevation or subsistence, these
subterrancan tremoIs, growing pains
we might call them, must be regarded
as evidence that the building of the
Alps is not yet complete process.
Again, along the oceanic borders of the
continent, earthquakes are of frequent
occurrence. Continents are areas that
have been appraised; oceans lie in basins
that have subsidized. The tracts be-
tween these two regions Of opposite
movement may not improbably be
specially liable to be affected by stresses,
the sudden relief from which will gem
crate earthquakes.-Archi6ald Geite, Ia
Good Words.